What's onboard: An intimate, classy ship with just 700 passengers, the Voyager is only suites, and generous 300-square-foot ones at that. It has all the basics - Broadway-style shows, a casino, a huge pool - but don't expect the climbing walls or ice rinks common to megaships. The main event is off the boat: the discovery of Europe's other sea, the Baltic.
What's to see onshore: Tired of doing touristy Rome? This northern cruise takes you to a number of gems off the beaten path, like the ancient walled city of Tallinn (the capital of Estonia) and the 13th-century medieval island of Visby. With three days in St. Petersburg, you can take in the vast art collections in the State Hermitage and still have time for an air tour to Moscow.
Alternatives: For other unusual itineraries, consider Crystal Cruises (which tours the Black Sea), Azamara (Russia) and Seabourn (Amsterdam, Antwerp and Dublin).
NEXT: For couples